As may be appreciated by anyone watching the 1995 America's Cup races off San Diego, even in the sophisticated America's Cup boats there is required that a bow man station himself at the bow of the sailboat and facilitate the jibing of the spinnaker by making changes to the guy sheets to permit the passage of the spinnaker pole, after its outboard end is lowered to permit it to swing through or dip to the rear of the forestay and move from the starboard side of the yacht to the port side or vice versa, where a connection is made to the opposite side guy. In larger sailboats each clew to opposite sides of the spinnaker along the foot has attached both a sheet and a guy. The active guy is released during a spinnaker jibe to one side of the forestay, and upon complete dipping of the pole about the back of the forestay, the new guy is attached to the spinnaker opposite side. Such difficulty is increased as a result of the bow of the yacht rising and dipping into the sea as a result of the wave conditions.
Dip pole jibing, where the outboard or distal end of the spinnaker pole is detached from the previously active guy as the boat shifts from a reaching condition to a direct downward state, has been improved over the years in an effort to reduce or eliminate the number of crew required at the bow and to perform all necessary control functions at or near the mast where the proximate or inboard end of the pole is swingably coupled to the mast.
U.S. Pat. No. 3,185,121 to Nilsen is an improvement over the basic dip pole spinnaker jibe system of the twelve meter yacht Vim which utilized a single retractable spring biased pin to selectively lock in a given guy to the end of the spinnaker pole. In the VIM jibing maneuver, the pin had to be pulled rearwardly against the spring bias to release the active guy, the pole dipped through and behind the forestay, and the new guy locked in. Nilsen, in the utilization of two side-by-side spring biased pins, permits the guys, after the ends are snapped into the respective clews of the spinnaker, to be locked into respective sides of the spinnaker pole at its outboard end. In such system, upon release of the active guy, the pole is permitted to swing across the bow under the forestay by releasing the spinnaker pole topping lift and pulling in on the after guy to the opposite side. The need for a bowman is then eliminated and all action takes place at or aft of the mast.
U.S. Pat. No. 3,207,114 to Moseley utilizes a similar arrangement for jibing the spinnaker while incorporating a locking mechanism within the outboard end of a hollow metal spinnaker pole to lock in special locking cones bearing rings coupled to the snap shackle bearing outhaul lines leading to the respective spinnaker clews. The pair of outhaul lines pass through the hollow spinnaker pole. When the active outhaul line is tensioned, with the pole to a respective side of the forestay at a desired position, the co-attached sheet to the snap shackle at the clew proximate to the spinnaker pole outboard end is then slacked. As a result, the tack of the spinnaker is automatically engaged by and securely locked to the outboard end of the spinnaker pole.
U.S. Pat. No. 3,228,372 to Ridder et al. utilizes, in a dip pole jibing system, a hollow spinnaker pole, port and starboard side jibing lines passing through the hollow pole and terminating in a ring sized larger than the ring-like fairlead at the outboard end of the spinnaker pole and being coupled to a respective guy. The inboard ends of the port and starboard side jibing lines pass through fairlead slots to the exterior of the pole end adjacent to the spinnaker pole pivot connection to the mast. The jibing lines are led through head knocker blocks which include jam cleats for locking the line at a desired position.
U.S. Pat. No. 5,109,786 to Hall is directed to an outboard end fitting for a spinnaker pole which is freely rotatable about the longitudinal axis of the pole and which provides on opposite sides of the axis a pair of fairleads for freely passing respective guys to the clews of a spinnaker. The free rotation of the fitting allows a tensioned guy to align to the respective fairlead, thereby avoiding twisting of that guy. Detaching and re-attaching of guys to the pole during jibing is avoided to facilitate dip pole spinnaker jibing without the necessity of a bow man.
U.S. Pat. No. 5,347,945 to McAlpine is directed to a spinnaker pole control system and a spinnaker pole outboard end fitting using double pairs of fore and aft rollers or pulleys vertically stacked and pivoting about a vertical axis at right angles to the longitudinal axis of the spinnaker pole, being closely spaced and between the peripheries of respective top and bottom rollers, port and starboard spinnaker pole brace lines are fed. The fitting is fixed to the pole and the orientation of the line feed passages as defined by the pulleys are rollers is highly restricted.
While the spinnaker poles and dip pole jibing systems as set forth in the patents discussed above eliminate the necessity for a bow man at the forestay during jibing, the spinnaker pole structure fails to segregate a plurality of lines including control lines passing through the spinnaker pole and to minimize friction on these lines under the heavy loads imparted by high velocity wind conditions acting on the spinnaker, resulting in line failure due to misalignment of the lines and the fairleads or pulley grooves, where sheaves are employed within the spinnaker pole apparatus itself.
It is therefore a primary object of the invention to provide an improved spinnaker pole for facilitating dip pole jibing without the need of a bow man, which preferably utilizes a single control line to each clew of the spinnaker which alternately function as a sheet for controlling the leeward edge of the spinnaker or a guy for fixing the weather edge of the spinnaker at the clew to the spinnaker pole, which preferably utilizes four lines led through the spinnaker pole and fed through articulating sheaves at circumferentially spaced positions about the pole at its outboard end to permit self-alignment of the sheave pulley groove to the axis of the guy line extending from the clew to the articulated sheave, while allowing the articulating sheaves to swivel or swing through 180.degree. or greater, thereby minimizing the friction between the control lines and the respective sheaves of the jibing system.
It is a further object of the present invention to provide a double swing axis sheave for a third, changing snatch guy which is mounted to the bottom of the spinnaker pole at its outboard end for swinging through dual pivot axes parallel to the axis of the pole such that the sheave may swing through in excess of 360.degree. for self-positioning parallel to an active sheave, either to the port side or starboard side of the yacht, to assist in controlling a new spinnaker to replace the existing spinnaker during changing of spinnakers.
It is a further object of the present invention to provide an improved spinnaker pole and dip pole jibing system which incorporates, as a fourth line within the hollow spinnaker pole, a baby topping lift line which is led through a fourth articulated sheave at the top of the outboard end of the spinnaker pole and connects to a conventional topping lift via single or double purchase arrangement, thereby permitting during jibing the dipping of the outboard end of the spinnaker pole by taking up the inboard end of the baby topping lift line through a fairlead slot at the inboard end and adjacent to its mast connection of the spinnaker pole.
It is a further object of the present invention to employ snatch guys as lines terminating in snap shackles carried by the hollow spinnaker pole, with the snap shackles loosely locked around respective guy and sheet primary control lines, solely connected to the respective clews of the spinnaker.